2006 325i Crankshaft Position Sensor Replacement
Diagnosis: Car took several seconds to crank. Idle was rough. Stuck in failsafe mode (2nd gear). Battery was not charging.
Advanced Auto ran the codes and it came back with Crankshaft Position Sensor and Transmission Control Sensor.
Pain in the ass to change... Forget it, if you have fat fingers or hands.
The crank sensor (cost $120 with new bolt) is located under the starter (which is under the intake manifold).
Access the sensor from under the car on the driver side.
This is a one handed, blind job. you have to do it all by feel.
you will need an 8mm socket to remove the tork bolt.
one little turn by the wrench and you should be able to remove the bolt with your fingers.
remove the old sensor, also remove the rubber gasket and reinstall it on the new sensor.
I hope this helps some people, as I had the worse time in trying to find the sensor and instructions on how to do it.
overall, it took me over 3 hours to this 20 minute job.
Good luck if you try to tackle this one.